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Testing the Discovery of Archean Terrestrial Mass-independent Sulfur Isotope Anomalies

测试太古宙陆地与质量无关的硫同位素异常的发现

基本信息

批准号：
0125096
负责人：
Douglas Rumble
金额：
$ 19.25万
依托单位：
Carnegie Institution of Washington
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2001
资助国家：
美国
起止时间：
2001-12-01 至 2003-11-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=0125096&HistoricalAwards=false
关键词：
Testing Discovery Archean Terrestrial Mass

项目摘要

AbstractEAR-0125096RumbleCarnegie Institution of Washington, Geophysical LaboratoryThe primary goal of this proposal is to confirm the discovery of mass-independent sulfur isotope fractionation by replicate analyses to validate accuracy and to identify mineral hosts of anomalous sulfur and measure its heterogeneity. The motivation for additional study of sulfur isotope analyses is because of their utility as biomarkers in ancient rocks. In Precambrian rocks where fossils are non-existent and organic residues have been converted to carbon, sulfur isotope mass-dependent fractionations remain as an indelible record of the vital processes of sulfate-reducing microbes. With the discovery of mass-independent sulfur isotope fractionations in Archean rocks, sulfur isotope geochemistry has acquired even greater significance. Such fractionations are known in the upper atmosphere where gas phase reactions take place under the strong influence of ultraviolet light. Sulfur isotope analyses, therefore, may give evidence for the former existence of life but they may also record a previously unknown chapter in the evolution of Earth's atmosphere. This proposal will examine the distribution of anomalous sulfur geographically in Archean and Proterozoic metamorphic rocks. Stratigraphic sections will be measured to establish a sulfur isotope fractionation time distribution. The new sulfur isotope laser fluorination microprobe at the Geophysical Laboratory of the Carnegie Institution will be used to do detailed examination of Archean and Proterozoic metamorphic rocks.

摘要EAR-0125096华盛顿隆布尔卡内基研究所地球物理实验室该提案的主要目标是通过重复分析来确认与质量无关的硫同位素分馏的发现，以验证准确性并识别异常硫的矿物主体并测量其异质性。对硫同位素分析进行额外研究的动机是因为它们可用作古代岩石中的生物标志物。在前寒武纪岩石中，化石不存在，有机残留物已转化为碳，硫同位素质量依赖的分馏仍然是硫酸盐还原微生物重要过程的不可磨灭的记录。随着太古代岩石中与质量无关的硫同位素分馏的发现，硫同位素地球化学变得更加重要。这种分馏在高层大气中是已知的，其中在紫外线的强烈影响下发生气相反应。因此，硫同位素分析可能为生命以前的存在提供证据，但它们也可能记录了地球大气层演化中以前未知的章节。该提案将研究太古代和元古代变质岩中异常硫的地理分布。将测量地层剖面以确定硫同位素分馏时间分布。卡内基研究所地球物理实验室的新型硫同位素激光氟化微型探针将用于对太古代和元古代变质岩进行详细检查。